8 Sided Polygon Rafter Table ( 8 - gon ) Octagon

8 Sided Polygon Rafter Table ( 8 - gon )

central angle = 45°
working angle = 22.5°
plan angle = 67.5°
miter angle = 4.97 & 12 (22.50°)
hip run per foot = 12.99
apothem multiplier = 1.08239
side wall multiplier = 0.82843

Pitch	Roof Angles		Frieze Block Angles		Hip Rafters					Jack Rafters
	Roof Pitch Angle	Hip Pitch Angle	Angle	Saw Bevel	Side Cut Angle	Backing Angle	Hip Drop 2x	Hip Drop 4x	Length Per-FT	Side Cut Angle	First 12” O.C.	First 16” O.C.	First 24” O.C.	Spaced 12” O.C.	Spaced 16” O.C.	Spaced 24” O.C.	Multiplier
0	0.00	0.00	0	22.5	22.50	0.00	0.00	0.00	12.99	22.5	30.63	40.29	59.60	28.97	38.63	57.94	2.41421
1	4.76	4.40	1.97	22.42	22.44	1.82	0.02	0.06	13.03	22.43	30.74	40.43	59.81	29.07	38.76	58.14	2.42258
2	9.46	8.75	3.90	22.18	22.26	3.61	0.05	0.11	13.14	22.22	31.05	40.84	60.42	29.37	39.16	58.74	2.44751
3	14.04	13.01	5.74	21.79	21.98	5.33	0.07	0.17	13.33	21.89	31.57	41.53	61.44	29.86	39.82	59.72	2.48851
4	18.43	17.12	7.46	21.29	21.60	6.95	0.10	0.22	13.59	21.45	32.29	42.47	62.83	30.54	40.72	61.08	2.54480
5	22.62	21.05	9.05	20.69	21.13	8.46	0.12	0.28	13.92	20.92	33.18	43.65	64.57	31.38	41.85	62.77	2.61540
6	26.57	24.79	10.49	20.02	20.61	9.85	0.14	0.33	14.31	20.33	34.25	45.04	66.64	32.39	43.19	64.78	2.69917
7	30.26	28.32	11.79	19.30	20.03	11.12	0.17	0.39	14.75	19.69	35.46	46.64	69.00	33.54	44.72	67.08	2.79494
8	33.69	31.63	12.94	18.57	19.43	12.26	0.19	0.45	15.25	19.02	36.82	48.42	71.63	34.82	46.42	69.64	2.90152
9	36.87	34.72	13.96	17.83	18.80	13.27	0.22	0.50	15.80	18.33	38.29	50.36	74.50	36.21	48.28	72.43	3.01777
10	39.81	37.59	14.85	17.10	18.17	14.18	0.24	0.56	16.39	17.65	39.87	52.44	77.59	37.71	50.28	75.42	3.14260
11	42.51	40.26	15.64	16.39	17.54	14.99	0.26	0.61	17.02	16.98	41.55	54.65	80.86	39.30	52.40	78.60	3.27505
12	45.00	42.73	16.32	15.70	16.92	15.70	0.29	0.67	17.68	16.32	43.32	56.98	84.29	40.97	54.63	81.94	3.41421
13	47.29	45.02	16.93	15.04	16.32	16.33	0.31	0.73	18.38	15.69	45.16	59.40	87.87	42.71	56.95	85.42	3.55932
14	49.40	47.15	17.46	14.42	15.73	16.89	0.33	0.78	19.10	15.09	47.07	61.91	91.58	44.52	59.35	89.03	3.70966
15	51.34	49.11	17.92	13.83	15.17	17.39	0.36	0.84	19.84	14.51	49.04	64.49	95.41	46.38	61.83	92.75	3.86463
16	53.13	50.93	18.33	13.27	14.63	17.83	0.38	0.89	20.61	13.96	51.05	67.15	99.34	48.28	64.38	96.57	4.02369
17	54.78	52.62	18.70	12.75	14.12	18.22	0.41	0.95	21.39	13.43	53.12	69.86	103.35	50.24	66.98	100.47	4.18638
18	56.31	54.19	19.02	12.26	13.62	18.57	0.43	1.00	22.20	12.94	55.22	72.63	107.45	52.23	69.64	104.45	4.35229
19	57.72	55.64	19.30	11.79	13.16	18.88	0.45	1.06	23.02	12.47	57.36	75.45	111.62	54.25	72.34	108.51	4.52106
20	59.04	57.00	19.55	11.36	12.71	19.16	0.48	1.12	23.85	12.03	59.54	78.31	115.85	56.31	75.08	112.62	4.69239
21	60.26	58.26	19.78	10.94	12.29	19.41	0.50	1.17	24.69	11.61	61.74	81.20	120.13	58.39	77.86	116.78	4.86600
22	61.39	59.44	19.98	10.56	11.89	19.63	0.53	1.23	25.55	11.22	63.97	84.14	124.47	60.50	80.67	121.00	5.04167
23	62.45	60.55	20.17	10.20	11.51	19.83	0.55	1.28	26.41	10.85	66.22	87.10	128.85	62.63	83.51	125.26	5.21918
24	63.43	61.58	20.33	9.85	11.15	20.02	0.57	1.34	27.29	10.49	68.50	90.09	133.28	64.78	86.37	129.56	5.39835

Framing Square usage Example: 8:12 Pitch
(Rafter Length Per Ft = 14.42) (Hip Rafter Length Per Ft = 15.25)
SS Angle = Speed Square Angle
Saw Angle produces compound Speed Square Angle
 
Tongue (8.00) Blade (12.00) for Rafter Plumb Cut Angle (SS Angle 33.69)
Tongue (12.00) Blade (8.00) for Rafter Level Cut Angle (SS Angle 56.31)
 
Tongue (8.00) Blade (12.99) for Hip Rafter Plumb Cut Angle (SS Angle 31.63)
Tongue (12.99) Blade (8.00) for Hip Rafter Level Cut Angle (SS Angle 58.37)
 
Tongue (5.38) Blade (15.25) for Hip Side Cut Angle (SS Angle 19.43) (Saw Angle 67.50)
Tongue (3.31) Blade (15.25) for Hip Backing Angle (SS Angle 12.26)
 
Tongue (4.97) Blade (14.42) for Jack Rafter Side Cut Angle (SS Angle 19.02) (Saw Angle 67.50)
 
Tongue (3.31) Blade (14.42) for Purlin Rafter Plumb Cut Angle (SS Angle 12.94) (Saw Angle 12.26)
Tongue (4.97) Blade (14.42) for Purlin Rafter Cross Cut Angle (SS Angle 19.02)
 
Tongue (3.31) Blade (14.42) for Roof Sheathing Plumb Cut Angle (SS Angle 12.94) (Saw Angle 12.26)
Tongue (4.97) Blade (14.42) for Roof Sheathing Cross Cut Angle (SS Angle 19.02)
 
Tongue (8.00) Blade (12.00) for Miter Box Gable Mould Plumb Cut Angle (SS Angle 33.69)
Tongue (8.00) Blade (12.99) for Miter Box 2 Cord Polygon Gable Mould Hip Plumb Cut Angle (SS Angle 31.63)
Tongue (4.97) Blade (12.00) for Miter Box 2 Cord Polygon Gable Mould Hip Cross Cut Angle (SS Angle 22.50) (Saw Angle 22.50)
 
Tongue (3.31) Blade (14.42) for Frieze Block Plumb Cut Angle (SS Angle 12.94)
Tongue (4.97) Blade (14.42) for Frieze Block Cross Cut Angle (SS Angle 19.02) (Saw Angle 18.57)
 
Tongue (3.31) Blade (14.42) for Square Cut Fascia Plumb Cut Angle (SS Angle 12.94)
Tongue (4.97) Blade (14.42) for Square Cut Fascia Cross Cut Angle (SS Angle 19.02) (Saw Angle 18.57)
 
Tongue (0.88) Blade (4.97) for Hip Rafter Square Cut Fascia Plumb Cut Angle (SS Angle 4.18)
Tongue (4.97) Blade (14.42) for Hip Rafter Square Cut Fascia Cross Cut Angle (SS Angle 19.02) (Saw Bevel Angle 18.57)